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Table 1
Cases and controls included in benign breast disease pathologic specimen collection^a
Cases	Controls	Selection of participants

1,080	4,353	Participants initially selected
-29	-85	Participant died or withdrew from study subsequent to selection
-265	-1,090	We did not pursue collection of specimens, because:
		• participant denied having biopsy or had cyst aspiration only
		• participant could not recall hospital or hospital no longer exists
		• participant denied permission to seek specimens
		• biopsy contained cancer
-379	-1,406	We were unable to obtain requested samples
		• specimens were no longer available or destroyed
		• hospital had no record of the patient or biopsy
		• hospital had no record of the patient or biopsy
-33	-113	Specimens received were not usable for study
		• slides were not of good quality/not evaluable
		• specimens did not contain breast tissue
		• were from wrong person or incorrect date
374	1,659	Eligible participants for whom we collected usable specimens

^aNurses' Health Study I (1976 to 1994) and II (1989 to 1995).
Tamimi et al. Breast Cancer Research 2005 7:R555 doi:10.1186/bcr1039

Table 1